The Columbia Encyclopedia, Sixth Edition. 2001-07.
gunmetal
a bronze, an alloy of copper, tin, and a small amount of zinc. Although originally used extensively for making guns (from which it received its name), it has been superseded by steel, and it is now chiefly employed in casting machine parts. The so-called 88–10–2 (copper-tin-zinc) alloy is the “government bronze,” composed of 88% copper, 10% tin, and 2% zinc. The percentages of the three elements are varied slightly in gunmetals produced for different purposes. The metal commonly called gunmetal today is very often steel treated to simulate the bronze alloy. In other cases, copper and tin are used alone; in still others, copper, tin, and lead are used.
